Research On Mechanical Structure And Control Strategy Of Electric Gear Type Automatic Clutch

This paper mainly implements the control strategy of single-motor drive at low speed and dual-motor drive at high speed for a pure electric vehicle driven by front and rear dual motors.According to this control strategy,an electric gear-type automatic clutch is designed,which can be engaged according to the driver’s intention.To achieve the purpose of switching between four-wheel drive mode and two-wheel drive mode of pure electric vehicles,the main content of the paper is as follows:(1)Using the clutch engagement and disengagement actions to realize the control principle of the power output and interruption of the front motor,propose the design scheme of the electric gear type automatic clutch actuator and control strategy,taking into account the ride comfort,comfort and safety of the vehicle,Proposed the design requirements that the electric gear type automatic clutch’s engagement and disengagement success rate should reach 100%,the engagement time sum is less than 0.7s,and the impact torque is less than 200Nm;for the design requirements and considering the complex vehicle conditions and the relatively high magnetic interference Many,put forward design requirements for the control motor in the clutch actuator,in order to select the appropriate motor,further analyze the advantages and disadvantages of the stepper motor and the DC motor;compare the existing clutch actuators on the market,and propose a new version of the electric gear-type automatic clutch Based on the design plan and structure optimization of the clutch actuator on the market,the deceleration and torque increase mechanism,the non-locking fork shaft mechanism,and the camshaft(shift drum)mechanism that converts curved motion into linear motion are proposed.(2)In order to make the clutch reach the target position as required,the square wave control method is used to control the forward and reverse rotation of the motor in the clutch actuator to realize the engagement and disengagement of the clutch;control the speed of the motor speed by controlling the duty cycle,in order to solve The constant speed of engagement and disengagement will cause the clutch actuator to be easily damaged.A control strategy based on the “slow-fast-slow” motor speed of the clutch actuator is proposed to dynamically adjust the PID parameters to achieve dynamic duty cycle output;Protect the clutch actuator can safely engage,add constraint conditions,design the clutch position self-learning control strategy and speed difference control strategy,only when the clutch movement position and stroke are correct and the speed difference between the driving motor speed and the wheel shaft end speed is less than 100 rpm.Perform the engagement action;in order to reduce the impact torque and shorten the engagement time,a fast engagement control strategy is proposed,which can save the engagement time by more than 150 ms.(3)The single-board test is used to verify the feasibility of using square wave control for the control motor in the clutch actuator.The experimental results show that the clutch control motor can change the direction of motor rotation according to the sequence of changing the Hall commutation,and use different duty cycles.The change in speed than the actual speed proves the feasibility of the square wave control method;the stability of the control strategy and the reliability of the actuator are verified based on the bench test.The test results show that the success rate of clutch engagement and disengagement actions is 100%,and the execution process is in progress.There is no damage to the clutch actuator,which proves the effectiveness of the self-learning control strategy and the speed difference control strategy;using the bench to simulate different accelerator pedal positions,engaging and disengaging during acceleration,the engagement time and disengagement time are both Less than 0.7s,the maximum impact torque is 191 Nm,which proves the effectiveness of the fast-engagement control strategy and the clutch actuator control motor "slow-fast-slow" control strategy;its engagement and disengagement time,impact torque,and engagement and disengagement in the vehicle test The success rate is basically consistent with the results of the bench test,which proves that the electric gear-type automatic clutch can still work stably under complex working conditions and magnetic fields.It also proves the reliability of the electric gear-type automatic clutch actuator and the feasibility of the control strategy.The electric gear-type automatic clutch meets the design requirements.